The effect of verapamil in the prevention of radiation-induced cataract

Purpose: Cataract is an unavoidable complication when radiation therapy inc ludes the lens, even in small doses. Alterations in the ion content of the lens were considered to play an essential role in cataract formation. In th is experimental study, the effect of verapamil on ion concentrations within the irradiated lenses was investigated in rats. Methods and Materials: Forty female Wistar albino rats, each weighing 180-2 50 g, were divided into three groups: (a) radiation treated (n = 10); (b) n o treatment (n = 10); (c) or a combination of radiation and verapamil (n = 20), Both the radiation group and verapamil-treated group received 5 Gy rad iation to the cranium in a single fraction, including the eyes, within the irradiation volume. All animals were sacrificed by bleeding, 7.5 weeks post treatment. Calcium, sodium, and potassium levels were measured in blood and in lens homogenates, However, for technical reasons, magnesium levels coul d only be studied in lens homogenates. Results: Potassium and sodium concentrations in lens homogenates did not di ffer in the control and radiation groups, but both were significantly lower in the verapamil-treated group (p = 0.001, p = 0.009, respectively). Calci um levels were higher in the radiation group and lower in the verapamil-tre ated group compared to the controls (p < 0.0001); magnesium levels did not differ (p = 0.37). Conclusion: Verapamil effectively decreased the lens calcium concentration, which is accepted as the key element in radiation cataractogenesis, It is therefore concluded that verapamil may reduce the risk of radiation-induced cataract formation. (C) 1999 Elsevier Science Inc.